Nowadays, various portable information terminals such as a tablet terminal (multifunction portable terminal) and a smartphone (highly functional mobile phone) are put on the market. An iPad (unregistered or registered trademark) is known as a typical example of the tablet terminal (multifunction portable terminal), and an iPhone (unregistered or registered trademark) is known as a typical example of the smartphone (highly functional mobile phone).
As is well known, a battery charger is often provided to each portable information terminal as an auxiliary part. The battery charger includes a battery-charging plug connector, which is fixed to one end portion of a power supply cable, and an adapter (transformer) including a plug, which is fixed to the other end portion of the power supply cable. When the portable information terminal is charged, in general, the plug of the adapter including a plug is inserted into a power outlet socket of a commercial power supply and the like, and the plug connector is inserted into a battery-charging receptacle connector formed in a lower end of the portable information terminal. Thus, a secondary battery (such as a lithium ion battery) built into the portable information terminal can be charged. Note that, in addition to the battery charging purpose, the receptacle connector and the plug connector are sometimes used as an interface through which data is input and output between the portable information terminal and other devices.
On the other hand, hitherto, various cradle devices (holding bases, battery-charging bases) capable of charging those portable information terminals while supporting or holding the portable information terminals on the cradle devices have been proposed.
For example, in Patent Document 1, there is disclosed a cradle device for holding a portable information terminal in a freely removable manner. The cradle device disclosed in Patent Document 1 includes an abutment surface for supporting a bottom portion of the portable information terminal, and a back plate for supporting a back portion thereof. A receptacle connector including a recessed portion and a protruding portion with an electrode formed in the recessed portion is formed at the bottom portion of the portable information terminal. The electrode of the receptacle connector is brought into contact with a contact point of a connector (plug connector) protruding from the abutment surface of the cradle device to be electrically connected thereto. This cradle device guides downward slide of the portable information terminal under its own weight by the back plate, and the plug connector is fitted into the receptacle connector when the bottom portion of the portable information terminal is supported by the abutment surface, to thereby perform electrical connection. Then, the portable information terminal is supplied with electric power to be charged.
In Patent Document 2, there is also disclosed a cradle device for holding a portable information terminal in a freely removable manner. The cradle device disclosed in Patent Document 2 includes a bottom wall for supporting a bottom portion of the portable information terminal, a back wall for supporting a back portion thereof, and right and left side walls for guiding side portions thereof when the portable information terminal is mounted on the cradle device. An engagement hole and a receptacle connector are formed at the bottom portion of the portable information terminal. On the other hand, a first opening and a second opening are formed in the bottom wall of a holding base on the left side and the right side, respectively. This cradle device further includes a hook that protrudes through the first opening of the bottom wall and rotates in such a manner that the hook can be engaged with the engagement hole of the portable information terminal, and a plug connector that protrudes through the second opening of the bottom wall and is supported by an elastic member. This cradle device, which also guides downward slide of the portable information terminal under its own weight by the back wall and the side walls and supports the bottom portion of the portable information terminal by the abutment surface, holds the portable information terminal with the hook. At this time, the plug connector is fitted into the receptacle connector to perform electrical connection. Then, the portable information terminal is supplied with electric power to be charged.
Further, the applicant of this invention also proposes a cradle device. This cradle device includes a body for holding a portable information terminal by a main mounting surface inclined with respect to a horizontal surface, and a battery-charging cover that includes a housing section capable of housing a plug connector and is removably fixed to a lower end of the main mounting surface. The battery-charging cover supports the lower end of the portable information terminal held on the main mounting surface, and is rotatable about pivots arranged at a lower end portion of the battery-charging cover. When the portable information terminal is mounted on or removed from this cradle device, the portable information terminal to be held or being held on the cradle device in a posture inclined backward rotates forward together with the battery-charging cover so that the portable information terminal is easily mounted on or removed from the cradle device.
Note that, although not relating to a cradle device, in Patent Documents 3 and 4, there are disclosed plug devices capable of being fitted into an outlet socket of a commercial power supply. Those plug devices each include a grip portion and a plug terminal that is rotatably fixed to a casing at one end of the grip portion and is to be connected to a receptacle terminal of the outlet socket. A protruding portion is formed on a side surface of the casing on one end side. When the plug device fitted into the outlet socket is to be extracted (removed), the casing is rotationally operated with a fulcrum that is a contact point between a surface of the outlet socket and the protruding portion so that the plug terminal of the plug device can be extracted from the receptacle terminal of the outlet socket with small operation force due to the principle of leverage. Note that, in the plug device disclosed in Patent Document 4, the protruding portion is used also when the plug device is to be fitted into the outlet socket so that the contact point between the surface of the outlet socket and the protruding portion serves as a fulcrum. Thus, the plug terminal of the plug device can be inserted into the receptacle terminal of the outlet socket with small operation force.